This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-287693, filed Sep. 21, 2000, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a head suspension assembly in which a head amplifier IC chip is mounted.
2. Description of the Related Art
In general, a magnetic disk apparatus is provided with a head suspension assembly in which a head serving as an electromagnetic conversion element for example, a magnetic head is attached to a slider and supported by a suspension. In the magnetic disk apparatus, an integrated circuit element including a read amplifier circuit for amplifying a signal read from a magnetic disk by the magnetic head and a write driver circuit for changing a direction and supplying a current to the magnetic head to allow the head to write data into the magnetic disk is generally called a head amplifier IC. The conventional head amplifier IC is generally mounted on a flexible printed wiring board (FPC) as a wiring cable member.
On the other hand, in recent years, as described in Jpn. Pat. Appln. KOKAI Publication No. 11-213365, it is proposed that the head amplifier IC should be mounted in the vicinity of the magnetic head, suspended by the head suspension assembly. Thereby, a length of a wiring pattern between the magnetic head and the head amplifier IC is shortened, an inductance and capacitance of the wiring pattern are reduced, and an electrostatic breakdown is prevented from occurring during connection of the magnetic head to the FPC.
Moreover, when the head suspension assembly with the head amplifier IC mounted thereon in this manner is assembled with the magnetic disk apparatus, the head amplifier IC is positioned in the vicinity of the surface of the magnetic disk. Therefore, in order to thin the head amplifier IC, a so-called bear chip having no package formed of a synthetic resin or the like is used as the head amplifier IC.
However, the head amplifier IC constituted of the bear chip as described above is formed by using a dicing blade or the like to cut a silicon wafer with a circuit formed thereon in a desired size in a manufacturing process. In this case, a micro break or crack of the order of 20 to 30 xcexcm is generated in a portion which directly contacts the dicing blade. Even when various technical countermeasures such as optimizing of the dicing blade and study of an adhesive material are performed to solve the problem, it is difficult to physically completely eliminate the break or the crack.
The head suspension assembly mounted with the head amplifier IC broken or cracked in the manufacturing process is assembled into the magnetic disk apparatus. In this operation, it is expected that the break or the crack of the head amplifier IC grows by vibration/impact caused by external factors, and a broken piece falls down on the surface of the magnetic disk in a worst case. Moreover, it is considered that the fallen broken piece is dragged on the surface of the magnetic disk by the magnetic head slider, the surface of the magnetic disk is damaged and magnetically recorded data cannot be read.
The present invention has been developed in consideration of the aforementioned respect, and its object is to provide a head suspension assembly which is improved in reliability.
According to an aspect of the present invention, there is provided a head suspension assembly comprising: a suspension; a wiring pattern disposed on the suspension; a magnetic head including a bear chip, mounted on the wiring pattern, and configured to record/reproduce information with respect to a magnetic recording medium; and a head amplifier IC mounted on the wiring pattern, and configured to amplify a read signal of the magnetic head, an outer surface of the head amplifier IC being coated with a resin.
According to another aspect of the present invention, there is provided a head suspension assembly comprising: a suspension; a wiring pattern disposed on the suspension; a magnetic head including a bear chip, mounted on the wiring pattern, and configured to recording/reproduce information with respect to a magnetic recording medium; a head amplifier IC mounted on the wiring pattern and configured to amplify a read signal of the magnetic head; an under fill charged between the head amplifier IC and the wiring pattern; and a resin tape coating an outer surface of the head amplifier IC.